A satellite such as an artificial satellite acquiring required information while making a predetermined orbit around the earth is provided with an attitude control apparatus so as to perform a task along a given orbit. The attitude control apparatus applies driving force generated by a reaction wheel, a thruster, or the like, to the satellite in an appropriate direction, if necessary, to control an attitude of the satellite.
In order to accurately and precisely control the attitude of the satellite, driving force should be applied in each of three-axis directions of X, Y, and Z axes. Recently, as shown in FIGS. 1A and 1B, research into a satellite attitude control apparatus using a rigid ball in a scheme in which the rigid ball is positioned at a central portion, a plurality of electromagnets are disposed at an interval of 90 degrees around the rigid ball, and a current is periodically applied to the electromagnets to generate a rotating magnetic field in the rigid ball, such that Lorentz's force is generated in the rigid ball to allow driving force to be simultaneously applied to three axes, thereby controlling the attitude of the satellite by only one driver has been actively conducted.
At the time of controlling the attitude of the satellite using the satellite attitude control apparatus using the rigid ball as described above, a simulation is first conducted in order to test reliability and control capability of the satellite attitude control apparatus. To this end, other electromagnets are disposed above the satellite attitude control apparatus, and a current is applied to these electromagnets to allow the rigid ball to be magnetically levitated by generated magnetic fields to stay at a predetermined position without dropping due to gravity.
However, in the satellite attitude control apparatus as described above, since an electromagnet for providing a rotational torque to the rigid ball and two electromagnets for magnetically levitating the rigid ball are disposed above the rigid ball and power is simultaneously applied to these two electromagnets to generate the magnetic fields, interference between the generated magnetic fields by the two electromagnets occurs in that process, such that a rotation control of the rigid ball is not accurate, and a magnetically levitated position of the rigid ball is not constant. Therefore, it is difficult to actually apply the satellite attitude control apparatus as described above.
In addition, the rigid ball is out of a normal position or collides with a component disposed therearound by thrust applied to the satellite when the satellite is launched from the ground and many flight vibrations applied to the satellite until the satellite enters a normal orbit. In this case, the satellite attitude control apparatus may not accurately control the attitude of the satellite or may become an operation-disabled state.